The present invention generally relates to vacuum sewer systems.
Vacuum sewer systems are generally known in the art. One of the main problems with vacuum sewer systems is the noise resulting from the pressure differential providing the drainage or flushing function for the sewage and from the subsequent pressure equalization stage in the vacuum sewer system. In previous attempts to reduce the noise level, a two-phase function has been proposed. The two-phase system, however, increases the cost and space requirement for the system due to a larger number and size of additional components.
One object of the present invention is to avoid the above mentioned disadvantages and to achieve an efficient drainage function with a diminished noise level and by simple means.
Accordingly, standard components are utilized in order to reduce the space requirement for the system and to maintain sufficient economy. This is achieved by using the first sewer pipe, i.e. a so-called riser or branch pipe, conventionally connected directly to the discharge valve, i.e. the first sewer valve, of the source of sewage as an intermediate receptacle for the sewage during a first transport phase of the sewage.
A desired or sufficient volume, which is related to the so-called vacuum capacity of the intermediate receptacle, that is the first sewer pipe, can be provided by varying the length of the first sewer pipe.
In order to increase the drainage or flushing effect at a second transport phase of the sewage, a third valve means can advantageously be provided at the first sewer valve end of the first sewer pipe. Such a third valve means would be arranged as an aeration valve in order to deliver transportation air for the second transport phase.
By enlarging the pipe diameter directly after the outlet port of the first sewer valve, the noise level of the drainage or flushing function can be reduced. Such an enlarged diameter can advantageously be provided by a pipe section arranged downstream of the outlet port of the first sewer valve, advantageously a first pipe junction arranged between the outlet port of the first sewer valve and the first sewer pipe. The third valve means, i.e. the aeration valve, can advantageously be connected to the first pipe junction.
Another advantageous arrangement for providing a desired or sufficient volume for the intermediate receptacle is to provide the vacuum sewer system with a third sewer pipe at the first sewer valve end of the first sewer pipe. This arrangement provides for a further possibility to vary the volume of the intermediate receptacle, i.e. the vacuum capacity of the same.
The third valve means or the aeration valve can advantageously be arranged at the end of third sewer pipe opposite the first sewer valve end of the third sewer pipe.
As the first transport phase and the subsequent second transport phase of the sewage require a second sewer valve to be employed between the first sewer pipe and the second sewer pipe, the desired vacuum can advantageously be provided over the whole vacuum piping by a pressure equalization means, advantageously a connection pipe connecting said sewer pipes over said second sewer valve.
The system is advantageously provided with a control center for monitoring the function of the valves. One or more of the valves can be mechanically or electrically, or advantageously pneumatically operated. In the latter case the valve or valves are preferably vacuum activated valves using the vacuum prevailing in the vacuum piping and provided by the vacuum generating means for operating the valves.
The communication or connection between the prevailing vacuum and the valves through the control center is advantageously provided by tubing with interconnected solenoid valves for opening and closing the vacuum connections.